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The corrosion study of part aircraft at the site of spot welds in the salt spray environment
Němčíková, Eva ; Doležal, Pavel (referee) ; Pacal, Bohumil (advisor)
This bachelor’s thesis is focused on the corrosion study of part aircraft at the site of spot welds in the salt spray environment. The panel is made of sheet of aluminium alloy AlCu4Mg1, with surface coated with aluminium of purity 99,5 %, and of square shapes of alloy AlCu4Mg1, without coating. Square shapes are an angle cleat. The thesis deals with corrosion characteristics at the site of spot welds and in the area of contact between them. It deals with character of corrosion, frequency of occurrence and range of corrosive attack. From the data files were detected critical places of construction.
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Fatigue properties of EN-AW 7020 aluminium alloy
Kuběna, Martin ; Němec, Karel (referee) ; Věchet, Stanislav (advisor)
This bachelor thesis focuses on the fatigue properties of wrought aluminum alloy EN-AW 7020. The theoretical part deals with the properties and use of aluminum alloys and metal response to cyclic loading. The experimental section is concerned with the structure of alloy EN-AW 7020 and its mechanical properties, especially fatigue characteristics. The goal is to construct S-N curves in the high- and low-cycle region and determine the fatigue endurance limit at 10^8 cycles.
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The Material Selection for Bicycle Frames
Šály, Peter ; Petrenec, Martin (referee) ; Němec, Karel (advisor)
Bachelor's thesis summarises basic information about materials that are used for production of bicykle's frames. It concerns not only with common materials that are the most used nowadays, thus aluminium alloys and composite materials – carbon in the concrete, but it also pointed on the other, alternative materials. It also explains specific terms that relate to concrete materials or to their technological treating. Each material has listed characteristic which is objective thus measurable and it results from physical-chemical's properties and treating possibilities of concrete materials. It conveys assumption of frame behaviour made from this material. Subjective characteristic is also listed and it results from practice – from the feelings by real ride. Comparison of these two approaches resulted in conclusion which may help in choosing material for bicykle's frame which we have specific requirements on. Next thesis concerns with usage of concrete materials by various producers whether world producers or national ones, with orientation on brands which are interesting because of their treating of unusual materials or they are interesting because of their specific treating of common materials. There is a brief review of most used materials for concrete types of bicycle's frames at the end of the thesis.
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Comparison of selected mechanical properties of aluminum alloys and structural steels
Belháč, Jakub ; Svoboda, Pavel (referee) ; Vlašic, František (advisor)
The subject of this bachelor´s thesis is a description of selected mechanical properties of metal materials and their comparison within aluminium alloys and constructional steels. The most common mechanical tests to quantify the mechanical properties are described here. The mechanical properties of constructional steels and aluminium alloys are separately described in subsequent chapters as well as their division and possibilities of application. The connection between structure, chemical composition and mechanical properties depending on a heat-treating process is shown.
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New Aluminium Alloys in Aircraft Structures
Przeczek, Jan ; Šplíchal, Jan (referee) ; Klement, Josef (advisor)
This bachelor work deals with newly developed wrought aluminium alloys, designed for application in aerospace industry. The task of that work is to compare recent aircraft aluminium alloys with conventional alloys and indicate direction of progress in this field. The comparison is particularly focused on improvement of mechanical and/or technological properties of these alloys.
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Reactivity and controll of properties of metallic materials
Kouba, Jan ; Richtera, Lukáš (referee) ; Zmrzlý, Martin (advisor)
This study deals with properties of aluminum alloys that are used in aerospace industry, particularly with alloy 2024. In introduction, the fundamental questions of metallurgy of aluminum alloys and their basic properties are summarized. Then the specific parameters of alloy 2024 are commented. It is followed by short summary of aluminum inorganic chemistry and chemistry of its compounds. Next chapter is an introduction to corrosion and description of its particular forms. The following section sets out a summary of results of recent research in the field of aluminum alloys corrosion, some details about corrosion product analysis and published results concerning hypochlorites, what is the key substance in experimental part. The experimental part is focused on the influence of temperature and concentration of sodium hypochlorite solution on corrosion of Al 2024, cladded by pure aluminum.
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Nondestructive evaluation of corrosion damage of Al-alloys by in-situ AE monitoring and nonlinear elastic wave spectroscopy testing
Kober, Jan ; Převorovský, Zdeněk
This work investigates the possibilities of monitoring ongoing corrosion process by acoustic emission (AE) and of determining overall corrosion damage by the nonlinear wave modulation spectroscopy method (NWMS). Specimens made of Al-alloy L-beams simulating stringer reinforcements of airplane structure were studied. The samples were repeatedly immersed in sea salt solution. The acoustic emission activity was recorded in situ during corrosion process. Nonlinear parameters of the samples were measured in between corrosion tests by NWMS method. The current dynamics of a corrosion process was determined by AE, the amount of corrosion damage was corresponding to the nonlinear parameters obtained by NWMS.
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Effect of Number of ECAP Passes on Creep Behaviour and Microstructure of Pure Aluminium and Al-Sc Alloy
Král, Petr ; Dvořák, Jiří ; Kvapilová, Marie ; Svoboda, Milan ; Sklenička, Václav
Experiments were conducted to determine an effect of equal-channel angular pressing (ECAP) on the creep behaviour and the microstructure of pure aluminium and an Al-Sc alloy. The coarse-grained materials in their as-received states were subjected to ECAP at room temperature using a die, which had a 90° angle between the channels. Experiments show that ECAP reduced the average grain sizes of ~1µm and ~0.3µm for pure Al and Al-Sc. The grain sizes after 8 ECAP passes and subsequent creep exposure are ~12µm and ~2µm for Al and Al-Sc alloy, respectively. The fracture analysis and morphology of creep fracture surfaces of an Al-Sc alloy revealed the formation of shear bands which were orientated along the direction of the last ECAP pass. The application of ECAP method causes a substantial continuous decrease in the creep resistance of Al and Al-Sc alloy with increasing numbers of ECAP passes which can be explained by increasing contribution of grain boundary sliding to the total creep strain.
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